Trimethoprim is an antibiotic. It is used on its own or together with other medicines to treat certain bacterial infections of the urinary tract.
This medicine is also used to treat certain bacterial infection of the ear in children.
Take Trimethoprim exactly as directed by your doctor or according to the instructions on the label. Do not take more or less than instructed by your doctor.
You may take this medicine with food to reduce any stomach discomfort that it may cause. Try to take it at the same time each day.
This medicine is available as a tablet, oral suspension, or oral solution.
If you are taking the tablet, swallow it whole with a glass of water.
If you are taking the oral suspension or solution, shake the bottle well before you take it to ensure that the liquid is evenly mixed. Use the measuring spoon or cup provided to measure your dose.
The dose of this medicine will be decided by your doctor. Your doctor will advise you on the treatment timeframe depending on the type and severity of your infection.
Take Trimethoprim at regular intervals. Do not skip any doses. You must complete the entire course of this medicine. If you don't, the infection will not be properly controlled.
Take the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and return to your normal dosing schedule.
DO NOT double a dose under any circumstances.
If you often forget to take your medicine, let your doctor and pharmacist know.
Do not take Trimethoprim if you ever had an allergic reaction (e.g. rashes, breathlessness, swollen eyes) to this medicine.
Alert your doctor if you have megaloblastic anaemia (a condition in which the bone marrow produces unusually large, structurally abnormal, immature red blood cells) that is caused by folic acid deficiency, or any other blood disorder as this medicine may not be suitable for you.
Inform your doctor if you have the following conditions:
- poorly controlled diabetes
- hypoaldosteronism (deficiency in hormone called aldosterone)
- acute porphyria (an inherited disorder that may cause skin or nerve problems)
- liver disease
- kidney disease
Let your doctor know if you are pregnant or breastfeeding.
Be sure to check with your doctor or pharmacist before giving Trimethoprim to a child or the elderly. Children or elderly people may be more sensitive to the side effects.
If you are going for certain laboratory tests (e.g. blood creatinine or methotrexate levels), inform your doctor that you are taking this medicine.
Keep your appointments with your doctor. Your doctor needs to monitor your condition and check your response to the medication regularly. Routine tests (e.g. liver or kidney function, blood tests, electrolyte levels) may be done while you are being treated with Trimethoprim. Your doctor will advise you about how often you need to have these tests.
Trimethoprim may cause any of the following side effects: headache, nausea, diarrhoea, vomiting, rash and itch.
Some side effects may need immediate medical help. Alert your doctor quickly if you experience any of the following:
- rashes, breathlessness, swelling of the face, eyes or mouth
- severe diarrhoea or diarrhoea with severe stomach cramps or bloody stools
- unusual bleeding or bruising, feeling tired and worn out
- muscle weakness, cramping or numbness
- fast or irregular heartbeat
Inform your doctor if any of these side effects do not go away or are severe, or if you experience other side effects.
Inform your doctor and pharmacist if you are taking any of these medicines:
- medicines for high blood pressure or heart disease e.g. enalapril, irbesartan
- medicines for heart disease e.g. procainamide, digoxin
- water pills e.g. amiloride, spironolactone, hydrochlorothiazide
- heparin (blood-thinning medicine)
- phenytoin (medicines for epilepsy [fits or seizures])
- medicines used in organ transplant or certain immune disorders e.g. ciclosporin, azathioprine
- medicines for cancer e.g. mercaptopurine, methotrexate
- medicines for HIV infection e.g. lamivudine, zidovudine
- dapsone (antibiotic)
- pyrimethamine (medicine used to treat infections caused by a parasite)
- repaglinide (medicine for diabetes)
- rifampicin (medicine to treat TB, an infection known as tuberculosis)
This list does not include all medicines that may interact with Trimethoprim.
Always notify your doctor and pharmacist if you are taking any other medicines, including herbal tonics such as traditional Chinese medicines, supplements, and medicines that you buy without a prescription.
Avoid alcohol.
Store in a cool, dry place away from the reach of children.
Medicines must not be used past the expiry date.
Sign Out
